1. The Field of the Invention
This invention relates to novel yellow ortho carboxy, ortho'hydroxy azo dyes having a silver halide developing capability. The novel azo dyes of this invention are particularly useful for the preparation of yellow azo dyes having especially desirable performance characteristics in photographic products and processes.
2. Description of the Prior Art
Yellow dyes having a silver halide developing capability, e.g., a silver halide developing substituent, are known to the art. Such dyes, commonly referred to as "dye developers" are disclosed in the following U.S. Pat. Nos.: 3,134,672; 3,134,764; 3,135,604; 3,135,734; 3,141,772; 3,183,090; 3,201,384; 3,246,985; 3,252,990; 3,282,913; 3,306,891; 3,309,199 and 3,424,742.
As disclosed in these patents and, as those in the art know, dye developers essentially comprise a chromophore integrated with a silver halide developing substituent, usually a dihydroxyphenyl silver halide developing substituent. Dye developers are particularly useful in diffusion transfer photographic products and processes because of their capability in their nonoxidized form of being dissolved in aqueous alkaline photographic processing compositions and their capability of being oxidized in the presence of developed silver to provide an immobile or precipitated dye developer. This differential in mobility (or solubility) between the oxidized and nonoxidized form of a dye developer provides a diffusible pattern of nonoxidized dye developer during development of a photoexposed silver halide emulsion and the pattern can be transferred by diffusion to an image-receiving layer for viewing.
Of the yellow azo dye developers disclosed in the above patents, those considered to be most closely related to the novel yellow azo dyes of this invention are described in Column 3 of U.S. Pat. No. 3,141,772 by way of the following structure: ##STR3## where X is hydrogen or a lower alkyl, lower alkoxy, sulfonamido, or trifluoromethyl radical and X is positioned ortho to the --N.dbd.N-- group; R' is a lower alkoxy, halogen, lower alkyl, trifluoromethyl or sulfonamido radical; p is the integer 0-4 and Q is a ##STR4## where Z is a lower alkyl radical and each R.sup.2 and R.sup.3 is hydrogen or an alkyl radical or R.sup.2 and R.sup.3 together may be a divalent aliphatic radical and M is a lower alkylene radical.